JOHANNESBURG, South Africa – The Zimbabwean cleric and opponent of President Robert Mugabe who was accused of adultery after what was apparently a government sex sting said Tuesday that the Vatican had accepted his resignation as archbishop of Bulawayo.

In a written statement, the bishop, Pius Ncube, said he was stepping down “to spare my fellow bishops and the body of the Church any further attacks.” The Vatican confirmed the announcement in its own one-sentence statement, citing a church canon that “earnestly” requests the resignation of a bishop “who has become less able to fulfill his office because of ill health or some other grave cause.”

Ncube said he would remain a Catholic bishop. Some of his supporters predicted that his resignation would leave him freer to raise the humanitarian and human rights issues that had become the preoccupation of his work as archbishop in Bulawayo, Zimbabwe’s second largest city.

But some also expressed surprise that the Vatican so willingly accepted his resignation. While the church speaks out regularly on humanitarian issues, they said, it has had relatively little to say about the social and economic collapse in Zimbabwe, whose leader, Mugabe, is a Catholic.

The church has long recognized the spotty record of many African priests in maintaining their vows of celibacy but has yet to deal consistently with the matter. Pope Benedict XVI, however, has strongly opposed most political involvement by priests, although the church itself often takes political stands and exerts pressure on behalf of its beliefs and interests.

In his statement on Tuesday, Ncube said he was the target of “a state-driven, vicious attack not just on myself, but by proxy on the Catholic Church.”

The bishop said that he would continue to speak out on Zimbabwe’s political and social crisis.